We only went to the homes of people who did not mail in their census forms, which is probably close to 1/3 of the population. You were lucky to get only the short form. In 1980, when I worked for the Census Bureau, there were three forms of varying length. The longest form,which went to 1 of every ten households, took more than an hour to fill out. The information collected goes far beyond merely identifying the number of people living in a household.